The invention relates to a text processing device for employment with a typewriter having a memory device in which the information input by means of the typewriter keyboard is storable and may be re-worked, and which, as needed, controls a data output device, for example the printing device of the typewriter, in correspondence to the stored information.
In typewriters expanded to form text processing devices, storage devices are employed into which the information is initially input and subsequently or repeatedly read-out for reworking or transcribing. For such purposes, storage means are available, particularly electronic memories, but also magnetic storage media, as for example magnetic tape or magnetic disc memories. Any desired information can be input into such memories or input information can be changed as may be desired. The memory content is then available for output means of the typewriter. An example of such type of text-processing device is illustrated in my U.S. Pat. No. 4,130,884.
By means of so-called search criteria, which are to be input over the keyboard of the typewriter, it has become known to locate the specific text locations within the inscribed memory in order to effect a change in the memory content or in order to read out the memory content commencing from such location. The employment of search criteria for locating such text locations represents an alternative measure to further known addressing possibilities.
The known text processing devices offer very little protection against unauthorized interrogation or more particularly against unauthorized manipulation, i.e. changes in the stored information. Consequently, even in a device which is properly functioning, great care must be employed in the comparison of the original, desired text with the final clean copy in order to be able to exclude errors from an intentional, unauthorized manipulation of the memory content.
Proceeding from these concepts, the invention has among its objects the production of a text processing device which will provide the greatest possible protection of the stored information. It will be appreciated that only authorized operating personnel should be in a position to interrogate or to change correspondingly safeguarded information.
A text processing device which fulfills these requirements, in accordance with the invention, utilizes a comparison device which is connected with the memory device by switching units controllable by means of the comparison device for effecting completion of the connections between the memory device and the text processing typewriter, in the presence of coincidence of identification data received from the data memory with identification data supplied over the keyboard, and a control unit for the memory device for finding and evaluating a memory area in the data memory selectively containing the identification data.
In a next processing device constructed in accordance with the present invention, the connections between the typewriter and the memory device are initially open operatively disconnected by means of suitable circuit-technical measures. As a result, a connection of the two units cannot be directly effected by an operator. The switching unit for completing the connections between the memory device and the text-processing typewriter are controllable in the present invention only by means of the comparison device, i.e. only when identification data is input by the operator, over the keyboard of the typewriter, which corresponds to the identification data supplied to the comparison device from the memory.
The control unit for the memory device, provided in accordance with the invention, serves to locate the memory location containing the respective identification data involved. Since the two units are separated from one another until the presence of a positive comparison result between the identification data supplied by the text-processing typewriter and that supplied by the memory device, it is likewise impossible to remove the stored identification from the data memory. If a basic identification, which imposes no limitation in the access to the data memory, is stored in the memory area of the memory device, provided for the identification, the comparison device completes a connection between a memory device and the text-processing typewriter without any kind of identification input over the keyboard.
According to a preferred embodiment of the invention, the switching unit provided in the text processing device is controllable by the read unit of the memory device, as a function of the scanning position in the data memory, which switches the output of the read unit from the data output device over to the comparison device upon existence of the identification area in the data memory. By so doing, it is guaranteed that only the information residing in the identification area of the data memory is supplied to the comparison device. The remaining data memory content, on the other hand, cannot be supplied to the comparison device.
Preferably, two memory modules are preconnected to the comparison device, one of which receives the identification data from the data memory, and the other of which receives the identification data supplied by the keyboard. Upon termination of the read-out of the stored informational content or reworking thereof, such memory modules are erased.
In accordance with a further preferred embodiment of the invention, the text processing device thereof is provided with a manually actuatable switch unit for the further operation of the control unit for locating an identification area and for switching off the data output device. By means of these additional elements, it is possible to input a new identification at the identification area provided therefor without this identification having an external effect by being printed out. Thus, only the person inputting the information is in a position to affect the data memory so safeguarded. However, if it is desired to also indicate the identification, contained in the memory data, on the original written draft, the text processing device is additionally provided with a hand-actuatable bridging switch disposed in parallel to the switching section of the manual actuatable switch unit which disconnects the data output device.